Rob sat her on a bench at the base of the wall. “I think you can. A lot of people have the wrong idea about climbing. They assume it’s all about arm strength and dangling off ledges by your fingertips, but your legs are the key to making progress. You need your quads not your biceps for this, which means women instinctively climb better than blokes, because they’re less inclined to act like knobs and try to pose.”

Jem laughed in spite of herself. “I doubt you’ll ever have a student less inclined to pose.”

He gave her his hand and pulled her up. “Smashing. Right, let’s crack on.”

His introduction to the basics was thorough and punctuated by practical examples. “Use your feet, put your weight over your feet, put your waist over your feet,” he told her, hopping on and off the wall with enviable poise. “Okay, come and have a go.”

Snug in a harness far more orthodox than the one she’d hashed together on Barton Bridge, and belayed by Rob’s colleague, she took her first tentative step on the wall. Rob joined her on a parallel hold.

“Don’t look up, look down,” he said. “Plan where you’re putting your feet, not your hands.”

It was sound advice, and she plotted her next couple of moves with relative ease, advancing halfway up before she made the mistake of glancing beyond her shoes to the crash mat below.

“Jesus,” she hissed. Perspiration slicked her palm, and her right hand slipped from its hold, flailing in midair until she found an alternative grip. Her knuckles blanched, and she thought she might be sick.

“Take a minute, Jem,” Rob commanded, pulling her attention away from the floor. She nodded in fitful jerks, reminding herself that even if she fell, the top rope would catch her. But what if it didn’t?

“Sorry,” she said. “Me and heights, we don’t really get along.”

He barked a laugh. “Now you bloody tell me.” He moved across to her, close enough that he could speak without his colleague overhearing. “Do you want to stop?”

“No.” She didn’t want to give in. She wanted to get to the sodding top.

He considered her carefully for a moment and then waved her onward. “Okay, good. Where are you going next?”

“There, I think.” She sidestepped onto a conveniently placed hold and gained another foot.

“You’re a natural,” he said, ignoring his mobile phone as it chirped.

She stared at him and dried her forehead on her sleeve. Her shirt was soaked and clinging to her, and her legs felt like wet spaghetti. “Bugger off,” she said, forcing the words out between mild bouts of wheezing. “And shift your arse off that spot. I need it.”